161651840 has 64 divisors (see below), whose sum is σ = 441668160. Its totient is φ = 55421952.

The previous prime is 161651839. The next prime is 161651869. The reversal of 161651840 is 48156161.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×161651840² = 52262634750771200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 161651797 and 161651806.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13562 + ... + 22521.

It is an arithmetic number, because the mean of its divisors is an integer number (6901065).

Almost surely, 2^161651840 is an apocalyptic number.

161651840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161651840 is an abundant number, since it is smaller than the sum of its proper divisors (280016320).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161651840 is an equidigital number, since it uses as much as digits as its factorization.

161651840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36109 (or 36097 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 32.

The square root of 161651840 is about 12714.2376885128. The cubic root of 161651840 is about 544.7453738598.

The spelling of 161651840 in words is "one hundred sixty-one million, six hundred fifty-one thousand, eight hundred forty".